The present invention relates to open-end spinning apparatus and, more particularly, to an open-end spinning apparatus with a spinning rotor having a rotor shaft supported in a wedge-like gap, or spandrel, between two spaced pair of support rollers and driven by an individual drive motor.
It is especially important in the continuing development of open-end spinning machines that, in addition to improving the quality of the yarns produced, the production output of such textile machines is increased. The speed of the spinning rotor is primarily determinative of the production output of open-end rotor spinning machines. For this reason, various drive and bearing variants have been developed for spinning rotors over the course of past years which make it possible to achieve rotor speeds above 100,000 rpms.
In the embodiment most frequently used in practice, two pairs of disk-like support rollers are provided in spaced relation about adjacent rotational axes for supporting the axial shaft of the spinning rotor in the wedge-like gap, or spandrel, defined by the rollers, with the rotor shaft being driven by a tangential belt which biases the shaft into the gap. The axes of the support disk pairs are slightly out of parallel to intersect one another at an acute angle, so that a force component directed on the end of the rotor shaft is produced. The necessary axial support of the rotor shaft takes place in these known rotor spinning devices preferably via a mechanical axial bearing or via a magnet bearing, as is shown by way of example in German Patent Publication DE 40 22 562 A1.
Another spinning apparatus which has a comparable support arrangement for the rotor shaft is described in German Patent Publication DE 37 34 545 A1. This publication discloses, among other things, a variant in which the individual spinning rotors are not driven by a common tangential belt running the length of the machine but rather are driven by individual drives. In this case, the rotor shafts of the individual spinning rotors are each biased into the support roller gap by a drive roller engaging the rotor shaft in opposition to the support rollers and driven by an electromotor. Although the publication explains that rotor speeds of greater than 150,000 rpms can be achieved with such a device, this known device has not been accepted in practice.
Single-motor drives for spinning rotors are also known from Japanese Patent Publication JP-A 60-224823 and German Patent Publication DE-OS 22 03 586.
Japanese Patent Publication JP-A 60-224823 discloses a spinning rotor supported with its rotor shaft supported in a bearing formed of support-disk pairs with an electric drive operating on the rotor shaft in the area between the support disks. Specifically, a rotor armature fixed externally to the rotor shaft rotates in a stator fixed to the support body of the support-disk bearing or to the spinning-box housing.
German Patent Publication DE-OS 22 03 586 describes a similar device wherein the individual electric drive is also formed by a rotor armature fixed externally to the rotor shaft and by a stationary stator arranged on the spinning-box housing. The drive can be arranged either on the end of the rotor shaft or as in Japanese Patent Publication JP-A 60-224823 in the area between the support disks.
These devices have the particular disadvantage that it is not possible to exchange the spinning components without expensive mounting work on the spinning unit since spinning rotors designed in this manner can not be readily removed to the front out of the rotor housing as is customary in other known open-end spinning machines, e.g., those machines having spinning rotors driven via tangential belts.